ts990sI’ve been operating the Kenwood TS-990S for some months now, so it’s about time I actually review it. This review reflects operation under firmware 1.05 as downloaded from the Kenwood website.

Because there have been a number of reviews that have done an excellent job of enumerating the radio’s features, I’m going to come at this differently. I’m going to first give you an overview of how well I think it operates and how comfortable I’ve become (or not) with its features, along with an assessment of its value with regard to its capabilities. I’ll note a few things that seem unique to me, standout features that are really special from the operations standpoint.

Then I’m going to lay out, in detail, the critiques I have of the radio from an operating point of view — that’s something no one has really gone into as far as I know, and I hope you’ll find it useful. I even nurse a vague hope that Kenwood will, via Google-fu or some kind soul, find this and take some of my ideas to heart, because I really do think the radio could be significantly improved with just a firmware upgrade (or several.)



The TS-990S is a big radio, and it is heavy. It feels more like a linear than a typical HF rig, part of which, no doubt, is due to the 200 watt capable transmitter. Once you set this thing on the shelf, moving it is quite an undertaking, the more so if you’ve got a bunch of cables attached, as you probably will.

I really like having four separate antennas, and being able to use one for receive and one for transmit (see my tips below.) The receive loop is well thought out, and has, in conjunction with the Ethernet interface, enabled me to utilize an SDR operating in synchrony with the TS-990S’s tuning. That in turn means I have an ultra high resolution, high speed, feature-full waterfall and bandscope as compared to the capabilities the TS-990S offers natively.

The optical audio in and out seems tailor made for my Mac, which also has optical audio in and out, but unfortunately, because I’ve had to loop the optical output back to the input in order to enable recording and playback of receive audio, I can’t use these connections that way. More about that in the gripes below.

The main and sub displays provide lots of information, even more than you’d think upon initial viewing, and for the most part I find them to be well designed and thought out. Exceptions to that in the gripes below as well.

One general observation is that even without digging into the menu system, which is extensive, the front panel provides direct access to a very large number of conveniences and amenities such that the radio is simply a pleasure to operate — I honestly look forward to sitting down with it each day and going off on my various SWL and ham explorations.

The radio’s metering is superb. In bar graph mode, during transmit, I can see power out, ALC level and any one of swr, Id, compression, Vd, or temperature. During receive, you get an s meter. But there’s a wonderful emulation of a traditional s meter as well as these bar graphs, and I just love watching that thing – even though it shows far less information than the bar graph on transmit, it’s just so pretty that I prefer it anyway.

The shortwave dial is a unique feature only, as far as I know, found on the TS-990S. It’s very cute, up to and including the custom s-meter displayed in that mode. In addition, the band up/down controls allow you to hop from one SW band to another quickly and easily, while the radio keeps track of your tuning separately for each band. Very trick. Love it.

Between receiver equalization, shift/width or high/low edge controls, roofing filters, speaker filters, the notches, noise blankers and noise reduction tools, the radio provides simply outstanding control over received signals. There are some shortcomings in the individual tools as noted below, but overall, I give it about a 9/10 rating here, much higher than any other non-SDR radio I’ve had the pleasure of using.

The radio provides a myriad number of ways to change frequency. Two tuning knobs, both of which are customizable. The MULTI knob can also serve as a third tuning knob. Keypad entry. RIT/XIT. Main memories. Quick memories. Band stacking registers. By HAM band. By SW band. Two general coverage VFOs. Via network commands and therefore by tuning external programs and radios. From the PF programmable function keys. It’ll tune as slow as 1 Hz if you like, and step as large as 9 or 10 kHz when that’s appropriate, plus it’s smart enough to let you set those things independently per demodulator mode. If you’re an inveterate knob twister and button pusher as I am, you’ll be in tuning nirvana. And it is rock-solid stable — I have never seen it detectably off frequency anywhere, on any band.

Switching between main and sub VFO control is trivial, and the display and some LEDs make it very obvious what you are doing. You would think the potential for confusion would be there with all those controls and features, but Kenwood really did it right and so operations are quite smooth and easy to understand. The only caveat is that there are so many features and functions — even without going menu diving — that it does take a while to learn your way around the radio. You probably won’t ever wrap your head around the things it can do in the modes you don’t use; for instance, I’m not really a CW guy although I did get my extra class license in those times when you had to demonstrate competence at 20 wpm. Consequently, I’m only vaguely aware of the CW features of the radio, and all I can tell you is that there are a lot more of them than on any other radio I’ve used. CW operations are a whole ‘nuther world, just as digital operations are.

The back panel is a joy; at first, it seems too empty, but with ethernet, optical audio, analog audio, USB, DVI, four antenna connectors and a full receive loop, accessory connections, power and more… after a few minutes of letting it all sink in, I realized that it wasn’t so much that the back panel was short connections as it was that the back panel was so big that they just didn’t need all that space. Other than an IF output, there is very little lacking that I would ask for (see below, I do ask for one.)


I’ve had the opportunity to upgrade the radio’s firmware, and I have to say I really like the way it works. Basically, you format a memory stick on the TS-990S. Then you download the file on your computer. Plug the memory stick into the computer and drag the downloaded file to it. From there, you just insert the stick in the front panel of the TS-990S and follow the simple upgrade instructions in the operator’s manual. Piece of cake, and no worries your computer will crash in the middle of the upgrade or yank the USB cable out, bricking the transceiver. Furthermore, since no custom software is required on the computer side, this works perfectly with Windows, OSX and Linux. Or anything else you might be running that understands memory sticks. Kudos to Kenwood for getting this exactly right.

Transmit Side

The TS-990S makes available several transmit bandwidth settings, and can transmit extremely high quality sideband audio up to four kHz wide. There is a 17-band plus level audio equalizer you can apply to your transmit signal, allowing wide adjustment I would think would allow you to use any imaginable microphone and make it sound just the way you want. On top of that, there’s a decent switchable dynamics processor with independent in and out control knobs. I’m using a Heil PR-781, arguably serious overkill, and reports on my transmit audio are most satisfactory to me.

With a 200 watt maximum output, the TS-990S can put another half an s-unit on anyone’s receiver as compared to a 100 watt radio. When you use a linear with the TS-990S, that extra headroom means that the transmitter is truly just loafing along to supply 20 or 30 watts of drive — the radio never even gets warm. For that matter, running barefoot at 200 watts, I’ve used it for hours without noticing any undue heating.

Neat Little Somethings

Using Separate Transmit And Receive Antennas

Using the TS-990S’s TRACKING button, you can make the sub-receiver follow the main receiver. So press RX on the main receiver, and TX on the sub-receiver; then press M>S to copy the main frequency to the sub receiver, and now press TRACKING so it illuminates. At this point, you can use the MAIN and SUB buttons to separately assign antennas to the two. I use this to receive with a wideband Pixel Pro RF-1B loop antenna on 80 meters, while transmitting via an 80 meter vertical. The vertical is very noisy on receive, whereas the loop works wonderfully and adds the bonus of being directional — but you can’t transmit on it.

Retransmitting Receive Audio

This is actually a workaround for the firmware design flaw that doesn’t provide for re-transmitting normal receive audio that the TS-990S records with its front-panel REC, STOP and PLAY buttons (the radio immediately drops out of transmit if you press PLAY.) To get around this, just connect a short optical cable from the TS-990S’s optical output back to its optical input. Then you can use the TX Audio memory capability, available from the main display when the SCP button is used to disable both Bandscope and Waterfall. It’s not nearly as convenient as it would be if the PLAY button worked properly, but it gets the job done.

Summing Up

To sum up, I’m content that for the money spent, I got enough radio to make me feel like it was a very good deal, and to make me comfortable recommending it if someone expresses an interest in radios of this price class.

Which is not to say that it couldn’t be better. Oh yes, it certainly could. And that’s where I’m going to take you next.

Just one thing before we move on. I’m not really complaining that hard. I really like the radio, I plan to keep it until either it dies or I do, and if it does die, I would probably just go looking for another. What I am doing is (trying) to complain specifically enough that, given the winds are right and the masters at Kenwood are of open ears, the radio might be improved to be even better –for everyone’s benefit. Including mine, of course.

Irredeemable Design Flaws

No IF Output(s)

I suppose, given that the TS-990S has bandscope and waterfall capabilities, Kenwood may have decided that an IF output for SDR use would be superfluous. The problem is that the built-in bandscope and waterfall are extremely limited in update speed, time and frequency resolution, display control, and features as compared to those found in readily available SDR software. It would have been wonderful to have a standard, buffered IF output on the TS-990S. My Yaesu FTDX-3000 has an IF output, and it is awesome when used with an SDR. The only way to pull this off, or something like it anyway, with the TS-990S, is to split the receive output using an isolator back to the receive input and off to an SDR’s input, and then use external software to get the SDR to tune in synchrony with the TS-990S. I’ve set mine up to do that with OSX using an RFSPACE SDR-IQ, but the problem is you’re not actually looking at what the TS-990S is receiving; you’re looking at what the SDR is receiving. It’s just a shame. Still, it’s worth doing, just for the hugely improved bandscope and waterfall capabilities. One bonus is that because you have a waterfall externally, you can keep it off on the TS-990S and now you have more display space for the prettier meter designs.

EDIT 20140212: There is a tested design for an IF output using a Clifton Laboratories Z10000B Buffer Amplifier Board. The .ZIP file containing the design is hosted here (You’ll need to be a member of the Yahoo TS-990S group to access the file.) Thanks to W6NEK for the mod and the pointer. He adds that performing this mod will likely void your warranty. I view its very existence as additional encouragement for Kenwood to provide an official kit to do the same.

Use Of UTF-16LE For Network Communications

This is just completely weird. UTF-16LE is a 16-bit character encoding that nothing uses in the world of normal software. UTF-8 is the long-established standard, just about every computer in the world is set up to use, and expect, UTF-8. UTF-8 has the wonderful feature of incorporating the ASCII character codes in 8-bit form, which means that any command line utility or otherwise can directly speak this dialect. UTF-8 is also much faster than UTF-16, because when operating in English, it sends half the number of bytes down the network pipe in order to get anything done. In addition, UTF-8 fully provides for the Japanese character set, so there’s literally no reason not to use it. But since they did use UTF-16LE, anything written to talk to the radio has to take extra time and resources to convert from ASCII to UTF-16LE and back again. I find this design decision to be inexplicable; but although it is certainly a firmware issue, I can’t see them changing it, as it would now require all the support software to be re-written. Very, very unfortunate.

Touchscreen Sensitivity

The bottom line here is that the touchscreen requires too firm a touch. This is likely a hardware problem that derives from selecting too cheap a touchscreen. I don’t find this to be a big deal, though, as I decline to put fingerprints on my display screen anyway. I tune using a mouse on my SDR software display.

DVI Output

The DVI output, sadly, is just a repeat of the main display on the radio. With the main display, the low resolution of the data isn’t a big deal, because that LCD is small. But when you get it on a large monitor, it’s just the same thing, larger. Grainier. Dare I say, crude. Would have been grand if an external monitor gave you, for instance, higher resolution waterfall and bandscope, or more metering, or… well, you know.

Flaws Kenwood Could Fix

Pretty much every complex transceiver design has its flaws and strange design decisions, and as of firmware 1.05, the TS-990S is no exception. The good news is that as far as I can tell, every one of the following gripes could be addressed by Kenwood by a software and/or firmware upgrade; the question, as always, is… Will they?

So following are the issues I’ve identified, in no particular order:

No Mouse Control

The touchscreen, while seemingly a good idea, accumulates fingerprints if you actually use it. When that happens, your beautiful radio begins to look filthy. Would have been great if Kenwood had allowed for plugging in a standard mouse device into one of the front or back panel USB connectors. I’d point and click much more happily than I can say I am willing to fingerprint the radio.

S-Meter Accuracy

Bluntly, the S-meter reads incorrectly at all times. There is a standard for s-meters; S9 is supposed to indicate 50 uV at the antenna jack; going down, it’s 6 db per s-unit, and going up, it’s 10 dB per division, with signal strengths calculated directly from those db steps. The Kenwood uses a different standard, enough so that it becomes difficult to compare the radio’s performance with another, properly calibrated radio. I really wish they would fix this.

The Waterfall Display

The waterfall is kind of minimalist, lacking any real control other than a “reference level” that controls the level of the bandscope. You can move the signal up and down the bandscope so that the noise level can lie near the bottom, or higher up. This in turn controls how the signal triggers color use in the waterfall; when signals are at the very bottom of the bandscope, you get the lowest color (bright blue.) What is needed here is twofold:

First, a separate control that allows us to adjust the intercept of the signal with the waterfall color independently of the level it is being shown at on the bandscope. This allows you to still see the bandscope even at the low noise level, and it also allows the noise level to display as a relatively or perfectly pure color.

Secondly, we need to be able to set (at least) the brightness of that lowest bandscope color; the supplied blue is far too bright, and even under the best conditions, it makes the waterfall very difficult to read.

When the bandscope plus waterfall is set to fixed mode, it will update live as you tune, displaying a very intuitive readout of the radio moving up and down in frequency as you tune. However, in center mode, the waterfall stalls; it looks terrible and it isn’t particularly informative. This may be a consequence of the speed of the DSP(s) and the CPU(s) in the radio. I say that because within my SDR software, there’s no problem at all displaying the waterfall in either mode, fixed or center. If so, it probably can’t be fixed. But if it’s just a matter of treating the waterfall data a little more carefully as I am guessing it is, I would like to see it fixed.

Retransmitting Recorded Receive Audio

On the front panel, there are REC, STOP and PLAY controls. These, as you might guess, control the TS-990S’s ability to record received audio. As a recorder, the radio does very well. You can record to a USB device, or to internal memory. Fine so far. But if you push play and the TS-990S is transmitting, it immediately drops out of transmit mode, thus preventing you from re-transmitting the audio you’ve recorded. This is… inexplicable. This feature is available on so many other radios I couldn’t even attempt to sum them up. There should be a menu switch to allow re-transmit at the very least, or else the drop-out-of-transmit operation should be completely removed. If I want to play audio back without re-transmitting, I’ll just not push transmit. How hard would that be?

There is a work-around as noted in the “Neat Little Somethings” section above, but it does require you to dedicate both of your optical jacks to the purpose, which is a shame; and it does not operate with nearly the convenience of the front panel PLAY, REC and STOP buttons.

Variable Rate Tuning

Simple: Spin the main tuning knob fast, and the tuning rate increases. Make that increase programmable. So useful!

CW Decode

Although the TS-990S offers PSK and RTTY decode and encode, it does not offer CW decode. I find this… baffling. No one expects it to be perfect except with strong, machine generated CW, but in terms of code complexity, writing a basic or even fairly advanced CW decoder about as easy as anything ever is, and I simply don’t understand why it is missing. A big “Huh?” here.

Digital Noise Blanker

The TS-990S’s NB2 function works reasonably well if the signals you are trying to hear are weaker than the interfering impulse noise. However, as soon as the received signal reaches a particular threshold, the blanker stops working and the receive audio begins to sound terrible. In addition, the blanker width seems to be fixed; better to have it manually adjustable, as noise varies enormously in width as well as in intensity.

One effective way to implement an impulse noise blanker without these problems is to provide for two controls, one for width and one for threshold. If the impulse is above the threshold, the blanker fires for the duration set by the width control. This is how I implemented the blanker in my SDR software, SdrDx, and the result is that SdrDx can easily outperform the TS-990S in almost any impulse noise environment. As there are no more knobs available, the width control could be implemented as a menu setting and a network control parameter.

Notch / BEF filter Width

This is a simple one. The manual notch and the BEF filter (on minimum width) are both far too wide. Most heterodynes are very narrow single tones; there’s no need to chop out 300 Hz of audio bandwidth just to notch out a carrier. For wider interference, BEF can do the job; for narrow single tone interference, the TS-990S is noticeably lacking a properly tailored notch. I’ve not been very successful with the auto-notch at all, but since I couldn’t make it work, I’ve little experience and decline to criticize at this time. I may very well be doing something wrong there, as I can’t imagine Kenwood shipping it if it didn’t work at all.

ID Interval Timer

In most countries, we’re supposed to ID ourselves at certain intervals. It would be great if the radio could nudge us accordingly.

PF Key Execute Depth

Let’s say you want to set up PFA (a programmable button) to select between bar graph meters and the emulation of the “real” meter. In fact, this is how my TRS-990S is set up. So you have the bar graph up, and you press PFA… does the meter change? No. Instead, the menu comes up, and you have to do further menu selections to get what you wanted done. Sure, it’s a shortcut, but it doesn’t cut all the way to the chase and actually get the job done. In the case of the meter selection, there are three types, so I would have hoped that each press of PFA would select a different type, 1-2-3-1-2-3-1… and so on.

AGC Limits

The AGC settings are programmable. This is almost as good as having an actual AGC knob that is infinitely variable; it’s certainly a quick way to get to the fast, medium and slow values you’ve chosen. However, as far as slow AGC goes, the TS-990S simply doesn’t offer such a thing. The slowest you can set the AGC for is somewhere under a second; longer times, for instance five and ten seconds, are wonderful for certain types of signal conditions and types. But you just can’t do it. I’d like to see the maximum go from 20 to 200 or 500. When I want slow, I really want slow.

Sub Display

Ah, the sub-display. This is a very cool feature of the radio, and I have to say I absolutely love the tuning scale emulation. However, there are very few things you can do with the sub display in normal operation; you get audio spectrum display and the scale, and you get the main VFO frequency. You can turn off the scale (oh no!) and replace it with duplicated sub-receiver frequency information from the main display. Not very useful, and certainly less so than the audio spectrum and bandwidth indicators.

Now, on the main display, if you open the menu or the waterfall plus bandscope, the available space remaining is too small for the meter emulation, and so it automatically changes to a single bar-graph. Ick. What would be fabulous is if the sub-display put the meter (or meters… there’s a great multiple bar graph display that provides lots of information during transmit) up while the main display is too full to do so.

For that matter, the waterfall could be adjustable so that it isn’t so tall, and then you could have the nicer meters.

Windows-Only Support for Kenwood Software

Well, it is what it is. No linux support, no OSX support. As an OSX user, I feel this rather keenly. In my opinion, which no doubt is not that popular, if you release something that needs software to make it work fully, you should cover these three bases, or, at the very least, release the source code so that someone else (like me) can do it for you. I feel that Kenwood let me down here.

Some S/N Ratio Weirdness

Compared to my RFSPACE SDR-IQ, my copy of the TS-990S evidences noticeably poorer signal to noise ratio. Switching between them on the same signal, there’s a “rushing” noise present on low level signals in the TS-990S output that simply isn’t there with the SDR-IQ using my own demodulation software. On the other hand, when it comes to really weak signals, the SDR-IQ loses them before the TS-990S does. I don’t know what to make of it, other than to say that (a), this may be an alignment issue or problem with my specific TS-990S, or (b) it may be present in all the TS-990S units, and (c) it may be a consequence of them milking that last bit of sensitivity out of the receiver chain (these remarks address only the main receiver… I hardly ever use the sub-receiver as it has no roofing filter settings and I prefer to use those.)

And in Addition…

It would nice to have:

Role-Designated Antenna Jacks

If I hook my receive only loop up to any of the four antenna connections, and I, being without a clue because it’s morning, Monday, or really any day after the year 2000, press transmit while that antenna is selected, the TS-990S will agreeably turn my antenna’s electronics into a (very expensive) pile of toasted carbon molecules. I would very, very, very much like the ability to designate any subset of the four antennas as RX only, such that the TS-990S would refuse to transmit even if I told it to, until or unless I changed the designation to TX+RX. I am fully willing to admit this is a compensation for my own abject stupidity, general lack of oxygen, and habit of shooting myself in the foot just to see what happens, but man, those loops are expensive, so please, save me from myself.

Likewise, it would be even more fabulous to be able to tell the TS-990S that antenna one can only transmit if I’m on 80 meters, antenna two when I’m on 15 meters, and antenna three on any band at all, while antenna four isn’t allowed to transmit under any circumstances. Bury these functions as deep in the menus as you like, they are just the thing you could do that with because they would rarely change, just think of the increased reliability and equipment safety this kind of functionality would bring to the table.

Spectrum Display Gain

The spectrum is always displayed at a constant amplitude. It would be wonderful to be able to adjust the vertical excursion as it relates to signal level. This would also make the colors of the waterfall more useful by changing the effective contrast of the waterfall.

Completely Programmable Colors

For both the waterfall and the spectrum (and this is definitely in addition to the programmable signal/waterfall intercept, without which the waterfall is seriously crippled.)

Predictable (Programmable?!) Preamp Gain

The TS-990S’s preamp is schizophrenic. On 20 meters, it’s one gain. On 10 meters, it’s another. Stop that, please. Give us 10 db or 20 db or something, but not a bunch of unassociated values so we can’t even figure out what’s going on.

TS-990 Rating as Analog Radio

 0 - Truly awful
 1 - Bad... could be worse
 2 - Just barely usable
 3 - Reasonably usable
 4 - Usable performance
 5 - In-class (average) performance
 6 - A little better than average
 7 - Good
 8 - Very good
 9 - Excellent
10 - Truly awesome

Programmable Band Edges

Seeing as how bands differ between countries, this should be a menu item. What it would do is provide a visual indication on the bandscope and the tuning ring emulation whenever the band edges are visible. Optionally, it could prevent tuning past them. Probably should (optionally) beep when you hit the edge, too. This would be both handy and a boon to staying legal, which I’m sure (cough) we all want to do.

SP-990 Speaker

The Good

This is a pretty short list: The speaker matches the TS-990S very well in the visual sense, and it has four filters, two each for high and low frequencies, any or all of which can be used in any combination. The filters work pretty well. There’s a mute button and an A/B selection button, and a headphone jack. On the back, there are A and B inputs, as well as an output jack. All three of these are common RCA jacks.

The Bad

The TS-990S uses the left and right stereo channels to carry audio from the two receivers. But the SP-990 is a monophonic speaker; so there’s no ability to control the receive audio at this level. You could use two speakers; but as you probably have already determined, the SP-990 is hideously overpriced, and spending about $600 for nothing but a couple of mostly empty boxes is… painful.

The cabinet has some resonances, most unfortunately down around CW frequencies. Some users have reported success in damping these resonances by using automobile padding and acoustic foam; they also report higher fidelity response. You can check out the Yahoo TS-990S group for those undertakings.

SP-990 Rating as a Speaker

 0 - Truly awful
 1 - Bad... could be worse
 2 - Just barely usable
 3 - Reasonably usable
 4 - Usable performance
 5 - In-class (average) performance
 6 - A little better than average
 7 - Good
 8 - Very good
 9 - Excellent
10 - Truly awesome

When you plug the headphones in, the speaker is muted. That’s fine as far as it goes, but it also requires you to plug and unplug the headphones repeatedly as you switch between speaker and ear-cans. A modification you can find on the net changes the mute button from mute function to headphones/speaker mode control, and I highly recommend this. After all, mute is the same as turning the volume down on the transceiver, and there’s already a knob for that. The reduction in wear and tear on the headphone jack is substantial.

Lastly, the speaker is far too light. When you plug in the headphones, the speaker skates around on my desk. I plan to open it up, drop a good hunk of steel in it, and close it again so that it will maintain its position when I use it.